1. Technical Field
The present disclosure relates to a chemical vapor deposition apparatus.
2. Description of the Related Art
Demand for light emitting diodes (LEDs) and semiconductor light emitting devices has increased dramatically due to applications thereof in mobile phone keypads, back light units (BLUs) for liquid crystal displays (LCDs) used in monitors or televisions, and general illumination devices.
In accordance with this trend, research has been conducted in several ways. One approach has been to use a large diameter sapphire wafer (e.g. 6 inches instead of 4 inches) for growing a nitrite semiconductor or an oxide semiconductor (for example, GaN, ZnO) as an epitaxial thin film in a light emitting device. Another effort has been to introduce a batch type of metal organic chemical vapor deposition (MOCVD) technology that allows a large number of wafers (e.g. 25 or 50 wafers) to be produced at the same time when an epitaxial thin film is grown.
Particularly, in a batch type deposition apparatus, it is important to have uniformity in the thin film grown on a number of wafers. However, because a number of wafers are loaded and arranged in the batch type deposition apparatus, it may be difficult to maintain an air current in a stable state. Therefore, it is difficult to achieve uniform deposition of a thin film in the batch type deposition apparatus.